Electrical condenser



May 21, 929. s. RUBEN ELECTRICAL coNDENsER Filed Deo. 22, 1926 W M w n'ucnoz SAMUEL RUBEN t; h/.S tozmm 1%/ @MM Patented May 21, 1929.

SAMUEL RUBEN, F NEW YORK, N. Y.

ELEcrnreAL coNDnNsna.

application led December 22, 1926. Serial No. 156,308.

This invention relates to electrostatic condensers, and it relates more particularly to electrical condensers of the electrolytic type.

According to the terms of my invention the device consists ofl hlm-forming electrodes separated by an electrolyte composed of an hygroscopic material with a small percentage of a stabilizing solution and a neutral or slightly alkaline salt in suspension with sai'd stabilizing solution and said hygroscopic material and held in a fixed paste like density and concentration by an insulating gauze like textile, and suitable pressure applied to maintain close surface contact between the elec trolyte and the electrodes.

For the electrode material I prefer thin aluminum sheets having an oxide lm formed upon the surfaces before assembly, and as the electrolyte, ,glycerine having a relatively small amount of Water and having mixed therewith suspended powdered sodiumbicarbon ate, a small percentage of boric acid being present to stabilize the paste which has a sodium borate conte due to reaction of the boric acid with the sdium bicarbonate and to increase the conduc g'vitv of the mixture. In absorbing from the atmosphere suicient moisture to maintain the desired conductivity. the ionic conductivity of the condensers is held constant. This condenser combines the advantages of the aluminum oxide iilm type with that of the colloidal charge type, without the inherent leakage of the latter and the drying out of the electrolytic element of the former.

The preferred method of assembling the elements of this device is to apply the pastelike electrolyte mixture toa sheet of gauze spread over the oxide surface of the aluminum sheets, the electrolyte being then in the form of a layer about 1/16 inch in thickness. Over this should be placed the other electrode element, and the whole compressed for complete contact. If the elements are to be coiled another layer of the gauze and the paste electrolytey should be applied so as to keep the electrodes separated. The electrolyte permeates the gauze and iills the interstices establishing a layer over its entire area.

Forming the electrodes. or coating the surfaces with aluminum oxide maybe accomplished by connecting the sheets as the anodes in circuits in a bath of ammonium sulphate,

the oxide yserving to maintain the leakage at a low value.

With such a combination having a total surface anode area of 200 square inches, the condenser has a capacity of 1000 microfarads, with a leakage ol about 2 milliamperes at 10 volts, which for commercial purposes is negligible. From the standpoint of material cost aluminum electrodes are preferable; but the device gives more efficient results it the electrodes are magnesium with which, however, an electrolyte of powdered potassium fluoride and glycerine and a small percentage of calcium hydroxide should be used. The lower resistance of the electrolyte promotes the efficiency of the combination. But for commercial use, aluminum electrodes with the electrolyte of glycerine, boric acid and srliodium bicarbonate are considered most suita e.

For use with low voltage alternating current at potentials less than the decomposition potential of the electrolyte for electrodes with capacitance eiects, other materials, such as lead, may be employed. But for direct current application and high voltage alternating current, as for iilter circuit use, the leakage due to those materials is prohibitively excessive. The electrolytic lilm capacitance eil'ects when aluminum electrodes are used. reduce leakage and permit universal application.

Reference is madeto the accompanying drawings showing embodiments of the invention, in which,

Fig. 1 is illustrative of a flat plate condenser, cut away in part tp show the interposed electrol te and gauze; Fig. 2 kshows the device in coi ed form and Fig. 3, a section view of the latter.

Referring particularly to Fig. 1, 1 and 11 represent the gauze carrier for the electrolyte 3, and 2 and 21 the aluminum electrodes. In Fig. 3, 4 representsy an insulating cover between the outer aluminum electrode and the Wallo the metal container; at 6 are the condenser terminals.

What I claim is: I

f 1. An electrical condenser comprising film-forming electrodes separated by an electrolytemixture composed of an hygroscopic material an-d sodium bicarbonate with fan acidic stabilizing compound.

2. An electrical condenser comprising hlm-forming electrodes and an electrolyte mixture having therein lycerine, sodium bicarbonate and boric acida?.

i 3. electricalcondenserhaving.A aluiiii- 2o a neutral salt, en Vacidic' staloilzing'come' picity and Viscosity to aiiord a,plasticvmixl",- ,ture with Aseid, 'neutral salt and compound and'to maintain the watercontent'of theelecfj trolyte substantially at its initial'value'.'

'electrolyte condenseii having i num'electrodes lcoated with aluminumoxide, and j an electrolyte ymixture having thereinY -glycci'ines boric acid land sodium ybicarloona'tev coveiing'a dielectric Widel meshedcloth Ina-'- terialinterposed between the electrodes.

4f.. An electrical condenser comprisinglni formingelectro'des separated by a paste'clec'- hicle for'electical conduction amixtu-reof poundl andfa material. combining hygroscof;

" forming electrodes and an electrolyte mixture ln'pasteform comprising-as Sole vehicle for-electrical'iconducton a neutral salt, an

acidic stabilizing-pompoundand a material .combining hygifoscopmity and .viscosity to aford lplasticity, with said neutral salt :and compound 'andto inaintain'tlie water content ofthe lecfbly-te mixture Substantially at its ,initial "value said .electrolyte mixtureV permeating a' dielectric 4iif'ide'i'ne'slxed cloth', interposed-between tliefelectrodes'and actingr as a base toiiolcl-saicl' electrolyte in propel-.form between the'electrodesv. I .f

l An el'ef'rt'iolytic condense; comprising spaced. {film-forming i' electrodes, l a.. porous spaceifanl: a yiscidelectrolyte mixture etween tl'iegplente s,-t saidin'ixtui'e comprising a viscousmaterial and an' .electifolyte',"said visconsmaterial' serying'as a cairier'niedium 'or-sa1d"electrolyte and said viscous "inaterialandsid'spa'ce'ii loothserving tokee'p-the ,testimony Wlieiie'o'f, SAM-Una -has signed'hisv name to 'this speciiication5-this 

